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37 Cards in this Set
- Front
- Back
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What are atoms?
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tiny units that determine the properties of all matter; the smallest part of an element that keeps the properties of that element
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Who came up with the idea that atoms exist?
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Democritus
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What did Dalton come up with? When?
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the atomic theory in 1808; he said that every element is made of atoms and that they cannot be subdivided ( we now know that they can ) and that atoms of the same element are exactly alike and that atoms of different elements are different from each other and can combine to form molecules
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Where is a proton located?
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in the nucleus
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What is the proton's charge?
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+1
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Where is a neutron located?
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in the nucleus
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What is the charge of a neutron?
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no charge
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Where is an electron located?
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outside the nucleus in energy levels
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What is the charge of an electron?
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-1
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Do we count an electron's mass?
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NO - it is too small to have any effect or change
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Is an atom spacey?
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Yes; an atom is mostly empty space
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Why do the number of protons equal the number of electrons?
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an atom has no overall charge - they basically cancel each other out
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What did Bohr come up with and when?
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the model of an atom - 1913 - elevator floors and building model - he says that electrons orbit the nucleus like planets orbit a sun
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When did the modern theory of the atom come out and what does it say?
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1925 - it says that there is a nucleus in the center and that electrons don't ORBIT - they move around like in a wave and there are energy levels with orbitals in them and the amount of energy the electron has determines the energy level it is in
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How many electrons can the first energy level hold?
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2
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How many electrons can any other level but the first hold?
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8
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Which electrons have more energy, the ones on the first or last level?
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last level
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What is a mole?
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a counting unit that means 6.022x10 to the 23 power of whatever you are counting
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What is 6.022x10 to the 23 power called?
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Avogadro's number
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What is the periodic law?
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properties of elements tend to change in a regular pattern when elements are arranged in order of increasing atomic number or number or protons in their atoms
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What does a period in the periodic table tell you?
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Which energy level the valence electrons are in
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What do the elements in a group have in common?
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similar chemical properties
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What determines the chemical properties of an element?
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the number of valence electrons
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What determines the charge of an ion?
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the number of electron gained or lost during ionization
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What are positively charged ions called?
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cations
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What are negatively charged ions called?
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anions
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What is the difference between a neutral atom and an ion?
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In a neutral atom, the atomic number also equals the number of electrons, but this is NOT true for ions; in ions, the atomic number only equals the number of neutrons and protons - not electrons
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What the atomic number represented by?
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Z
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How do you determine atomic mass?
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add the number of particles ( protons, neutrons, and NOT electrons ) together
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How much does a proton and neutron weigh?
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1 AMU each
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What is atomic mass represented by?
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A
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How do you find the number of neutrons?
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A-Z
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What are isotopes?
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atoms of the same element ( same number of protons ) but having different numbers of neutrons
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An example of an isotope is:
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P-31
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In general, what is the atomic number about?
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protons
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In general, what are ions about?
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electronsIn
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In general, what are isotopes about?
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neutrons
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